RADIX_TREE_MAX_HEIGHT
struct radix_tree_node *stack[RADIX_TREE_MAX_HEIGHT];
struct radix_tree_node *temp[RADIX_TREE_MAX_HEIGHT - 1];
if (root->height == RADIX_TREE_MAX_HEIGHT) {
struct radix_tree_node *temp[RADIX_TREE_MAX_HEIGHT - 1];
if (root->height == RADIX_TREE_MAX_HEIGHT) {
struct radix_tree_node *stack[RADIX_TREE_MAX_HEIGHT];